This invention relates to a monitoring apparatus of a transport system which has a conveyor for a workpiece carrier adapted to accommodate components or component groups. The monitoring apparatus serves for determining the absence or presence of the workpiece carrier in a region of the conveyor.
The above-outlined conventional monitoring apparatus is used particularly in a transporting system in which an incoming and an outgoing conveyor abut one another at right angles and at the transfer location means are provided for detecting the presence or absence of the workpiece carrier.
At the transfer location a first signal transmitter of the monitoring apparatus is arranged which responds to a collision of a workpiece carrier with a stationary stop. The first signal transmitter is positioned at the transfer location. As long as such a signal is present, a separating element which is situated upstream of the transfer location as viewed in the conveying direction is in a stop position so that further workpiece carriers are prevented access to the transfer location. As soon as the workpiece carrier is fed into the transfer location, the first signal transmitter is deactivated. At the same time, a second signal transmitter of the monitoring apparatus is activated which monitors the departure of the workpiece carrier from the transfer location. As long as the second signal transmitter is active, the separating element continues to remain in a stop position. The separating element is switched into a let-through position only after the workpiece carrier has completely left the transfer location and the first signal transmitter and the second signal transmitter no longer detect the presence of the workpiece carrier, so that a subsequent workpiece carrier again may be moved into the transfer location.